Many young, smooth, thin-barked trees such as honey locusts, fruit
trees, ashes, oaks, maples, lindens, and willows are susceptible to
sunscald and bark cracks. Sunscald normally develops on the south or
southwest side of the tree during late winter. Sunny, warm winter days
may heat the bark to relatively high temperatures. Research done in
Georgia has shown that the southwest side of the trunk of a peach tree
can be 40 degrees warmer than shaded bark. This warming action can cause
a loss of cold hardiness of the bark tissue resulting in cells becoming
active. These cells then become susceptible to lethal freezing when the
temperature drops at night. The damaged bark tissue becomes sunken and
discolored in late spring. Damaged bark will eventually crack and slough
off.
Trees often recover but need TLC – especially watering during dry
weather. Applying a light-colored tree wrap from the ground to the start
of the first branches can protect recently planted trees. This should be
done in October to November and removed the following March. Failure to
remove the tree wrap in the spring can prove detrimental to the tree.
By: Ward Upham
